1. Technical Field
The present invention relates to bicycle speedometers, and more particularly, to a sensing unit for a bicycle speedometer, wherein the sensing unit has a positionally adjustable sensed member and therefore able to be aligned with a sensor of the sensing unit, so as to ensure the bicycle speedometer with a reliable signal related to bicycle pedaling.
2. Description of Related Art
With people's increasing awareness of the importance of environmental protection and individual health, cycling for both transportation and exercise has become a fashion. In this context, various accessories and tools are vigorously developed for the purpose of facilitating riding. A conventional bicycle speedometer typically includes a meter body for providing information and a sensing unit for detecting pedaling and generating a signal related to bicycle pedaling, so that the signal generated by the sensing unit can be processed into information about pedaling counts, frequency and/or speed of pedaling, and displayed through the meter body for the relevant cyclist to read as reference in terms of calorie consumption and so on.
Taiwan Utility Model Patent No. M386237 has disclosed a device for detecting pedaling frequency. The device is composed of a magnetic sensor fixed to a bicycle's bottom bracket and a turning table that carries thereon more than one magnetic member and is configured to rotate with the bicycle's crank, so the turning table facing the magnetic sensor can have the magnetic members alternately sensed by the magnetic sensor while the bicycle is pedaled and the crank is rotating. Thereby, the magnetic sensor generates a signal about the magnetic members that pass by, and the signal can be used to produce the data of pedaling frequency.
However, this prior-art detecting approach works on condition that the magnetic field generated by the magnetic members appropriately overlaps the sensing range of the magnetic sensor. Otherwise, the insufficient magnetic intensity would lead to sensing mistake. In addition, for different types of bicycle frames, the magnetic sensor fixed to the bicycle's bottom bracket has to be redesigned in terms of both size and position opposite to one that can readily fit all kinds of bicycles and be promotive to end-users' DIY installation.